My girlfriend seems to be having a similar problem. Her curve seems to be slow with a couple things. I have just upgraded from a Cingular 8125 to my 8700c and couldn't be happier, though I'll save my praise for another day and another post. Back to the topic at hand, she upgraded from a SLVR after seeing my 8700 and went for the curve. The messages on her main screen(Dimension-Today theme) stay there even after she deletes them, overall performance is sluggish, it wont send mms messages(she has unlimited data, 1500 messages, and unlimited m2m msgs), internet connection freezes often(im assuming this is just cingulars network), and it wont turn on or off(she has to remove the battery instead). Can anyone make any sense of this? Im trying to find out if any of this is common with the device or if we should go back to the Cingular Store and complain.
Thanks for any help you guys can provide. As I wrote before, I'll save my praise for this device and site for later, but this certainly is the greatest device ive ever used. The addiction is alive and well, and this site is an incredible resource. Thanks again.

Wow, there really seem to be quite some things wrong there with that curve.
I have a curve as well and don't have any of the problems you mentioned.
If I were you I would return it to the shop. The curve is a fantastic BB, so definitely give it another try